Air twisted, whirled and howled, hurling debris off brownstone rooftops and shucking trees from sidewalk plots. Cars flipped, people fled.
The tornado that struck Brooklyn in August 2007 cost tens of millions of dollars in damages, displaced dozens of residents and sent a warning to New York: The next one could prove catastrophic, especially in a city unaccustomed to such storms.
While the chance of a tornado striking New York City remains extremely small, the 2007 storm proved that it is not out of the question. On Saturday, as heavy rain, quarter-size hail and powerful wind battered the region, tornadoes skirted perilously close to the city, touching down briefly in three locations on Long Island, along with three more in Connecticut and Rhode Island, the National Weather Service said.
The next time a tornado hits the city, the consequences could be devastating, according to interviews with more than 30 experts, including meteorologists, engineers and government officials.
“Rare events by definition happen,” said Dr. Harold Brooks, a senior research scientist at the National Oceanic and Atmospheric Administration. “How you prioritize that kind of weather event, though, is a pretty hard policy question to answer.”
A small chance, but not one to ignore
Of the roughly 1,200 tornadoes that form in the United States every year, only a tiny number threaten cities.
There is about a 1 in 2,000 chance that a tornado will strike a building in Oklahoma City in any given year, said Paul Markowski, a professor of meteorology at Penn State University, citing data from the National Weather Service Storm Prediction Center. The odds of a tornado striking a particular target in New York City, he said, are lower: about 1 in 5,000.
But tornadoes appear in every state, killing about 80 people a year nationwide, and the danger to cities should not be dismissed, experts said.
“The atmosphere is agnostic about where the right conditions will come together,” Dr. Markowski said. “If you have Oklahoma or Alabama tornado conditions developing in New York, you’ll get an Oklahoma or Alabama tornado event in New York.”
Scientists have not yet determined whether a link exists between climate change and the frequency or strength of tornadoes, which are relatively small, short-lived storms. There is also limited data available.
But climate change is most likely increasing the number of days in which conditions are ripe for thunderstorms, which can spawn tornadoes, said Michael Tippett, a professor of applied mathematics at Columbia University.
Based on current climate models, the New York region could have about six more days a year of thunderstorm weather by 2100, said John Allen, a climate scientist at Central Michigan University.
“I wouldn’t say that New York is exceptionally vulnerable,” he said. “But that’s what makes it challenging in some respects, right? The rare event is the one that could have a considerable impact that people don’t necessarily anticipate or prepare for.”
The National Risk Index, an analysis created by the Federal Emergency Management Agency, ranked New York City at higher risk for tornadoes than states like Oklahoma and Kansas because the potential for damage was much higher.
“You see someplace that’s so densely populated with infrastructure, with buildings, with people — when an event such as this happens, there’s a consequence,” said Michael Grimm, assistant administrator for risk management at FEMA.
Readiness for a rare event
On Sept. 1, as the remnants of Hurricane Ida unleashed deadly downpours across the boroughs and threatened a tornado, officials warned residents in the Bronx and Manhattan to “take shelter NOW.”
But it is not clear how many New Yorkers have appropriate shelter, nor how many know what to do if a tornado strikes. A series of national surveys, done yearly from 2017 to 2021, asked 516 New York City residents how much time they believed they would have to reach safety after a tornado warning was issued. About 75 percent of them said they would have more than one hour. In reality, it’s about 15 minutes.
“You can imagine how dangerous that would be if people are thinking: ‘Well, the tornado warning came. I better hop in a cab and get home,’” said Dr. Joseph Ripberger, associate director of the National Institute for Risk and Resilience and an author of a study on the surveys. (Experts say cars are particularly dangerous during tornadoes.)
Some experts said that while the city had more urgent, climate-change-driven problems to address — namely hurricanes and flooding — more tornado education was needed.
“I work in disaster response, and I wouldn’t know what to do if there was a tornado,” said Amy Chester, managing director of Rebuild by Design, a nonprofit that works on infrastructure.
“New York is utterly unprepared for tornadoes, and we saw what happened when we were unprepared for the flash floods,” Ms. Chester said.
Heather Roiter, assistant commissioner of New York City’s office of emergency management, said the city was “always trying to get the message out about how to be prepared for emergencies, including tornadoes.”
She said the city was trying to focus “at the community level,” noting an event her office hosted in July in partnership with Oklahoma City’s emergency management agency.
Officials in Alabama, Texas and Oklahoma — states where tornadoes are more common — said that drills in which students walk to an enclosed area, away from windows, helped ensure that warnings were taken seriously even outside school.
Experts said this practice would be useful in New York, which mandates drills for fires and other emergencies but not for tornadoes.
Debris, ripped roofs and darkening skies
History shows some of the horror tornadoes can inflict on cities. In 1896, one killed 138 people in St. Louis. In 1925, a tornado killed nearly 700 people across three states, injuring 2,000 others and obliterating 15,000 homes. In 2020, several tornadoes shredded East Nashville, killing 25 in Tennessee.
What makes New York City especially vulnerable to a tornado, experts said, is its large population — largely unfamiliar with tornado safety — and its architecture, with many older buildings and an abundance of potential debris.
In Manhattan, a powerful tornado could cause billions of dollars in damage. In other boroughs, neighborhoods could be smashed and utilities seriously damaged.
“This summer was really a big wake-up call for this area, that we’re not immune to the effects of severe thunderstorms, and the perils that they bring, which includes tornadoes,” said Megan Linkin, a meteorologist and senior underwriter at Swiss Re Corporate Solutions, an insurance company.
“You would have an extreme amount of flying debris, and the debris causes extraordinary, life-threatening damage,” said Illya Azaroff, an architecture professor at the New York City College of Technology. Wind could make older buildings look “like a dog’s chew toy,” he said.
Buildings with flat roofs could be severely damaged, especially if cladding was unable to withstand wind suction, said Abi Aghayere, a professor of structural engineering at Drexel University.
Newer buildings and skyscrapers would most likely withstand wind, but projectiles could crack the glass exteriors of many buildings.
“No matter what building you’re at, you need to get away from the windows and get to an interior space,” said Anne Cope, chief engineer at the Insurance Institute for Business and Homes Safety.
If a tornado hits the city, experts said that residents should listen to warnings and immediately find shelter away from windows. Do not delay, go outside or watch as rain clouds darken the sky.
By the time the wind sounds like an oncoming train, they said, it will probably be too late to flee.